The present invention relates to a safety device for use in gas burners, which continues to supply the gas during the presence of flame of combustion. Widely employed safety devices for preventing any possible danger that would be caused by the emission of unburned gases were composed of a thermocouple heated by the pilot flame, and an electromagnetic means energized by the electromotive force of the thermocouple to safely shut off the flow of gas when the flame has been extinguished. According to the above mentioned conventional safety valve devices, the safety valve is maintained at an open position while there is the output from the thermocouple, and the safety valve is restored to the close position when the output has extinguished, providing increased safety performance, economy in manufacturing cost and extended life. The thermocouple, however, has a thermal capacity and continues to produce the output due to the residual heat. Therefore, some period of time was required before the electromagnetic device was sufficiently de-energized. The duration of this time is dependent upon the force for maintaining the safety valve at the open position and the resilient force of a spring or the like for restoring the safety valve to the close position. If the duration of time is long, the flowing amount of the live gas increases after the flame has been extinguished, and an extended period of time is required before the safety valve returns to the close position. A dangerous condition will be presented if the next operation is taken place neglecting the above mentioned period of time. For example, the safety valve starts from the completely close position and supplies the main burner fuel after having supplied the pilot burner fuel, after having ignited the pilot flame and after having confirmed the burn of the pilot flame; the safety is maintained by performing the operation in the order mentioned. However, in case the operation is started again before the safety valve is returned to the completely close position, the aforesaid order of operation is neglected. Accordingly, a variety of contrivances have been devised such that the safety valve is returned to the completely close position before the operation takes place again. Two such gas valves are shown in the U.S. Paul Dietiker Pat. No. 3,877,475 issued Apr. 15, 1975 and the U.S. Paul Dietiker et al Pat. No. 3,973,576 issued Aug. 10, 1976.